It all sounds uncannily familiar. In the last general election the left suffered its worst defeat for years. The main party of the right, led by a well-regarded and consensual centrist, came top of the poll. Even so, it needed the support of the third party, the liberals, which had had a good election under its personable leader, to form a coalition.

The two-party deal was quickly done, and with much goodwill. The new government started well, but the economic context soon worsened. Within months, poll support for the coalition began to ebb. But support for the junior coalition party slumped most of all. Its once popular leader became a hate figure. The coalition's survival now hung on a series of crucial upcoming electoral tests.

The parallels with Britain are so obvious as barely to need elaborating. For Merkel's CDU, read David Cameron's Conservatives. For Westerwelle's FDP, read Nick Clegg's Liberal Democrats. And, for the 2011 Länder elections, read this spring's Scottish and Welsh polls, as well as today's Oldham and Saddleworth byelection. If nothing else, this current northern European political lock-step ought to encourage the British political class to keep a rather closer eye on German events and take a less obsessive interest in much less easily translated American developments.

There are, of course, myriad differences between politics in Germany and Britain, not least in the two electoral systems. Germany's recent economic bounceback, its 3.6% growth rate in 2010 and its lowest unemployment rate in nearly two decades mark a dramatic contrast to the underlying picture in Britain too – though again these are not without vital long-term lessons for British politicians overly besotted with the American model. Yet, even allowing for many inevitable differences, the current comparability between German and British electoral politics is striking.

All this may seem like alarming news for Clegg and his party. Coalitions tend to be harder for the junior party, which gets less of any credit when things go well and more of any blame when they go badly. The collapse in the FDP's standing from 15% to 3% is proportionately similar to the Lib Dem slide in some polls here from 24% last May to 7% today. Clearly, both parties are in trouble, as are both party leaders. Equally clearly, both need to make a priority of revival strategies if they are to be effective in these or any future governments.

But it is not all gloom and doom for the FDP and the Lib Dems. For one thing, as both Merkel and Cameron have become well aware, electoral weakness paradoxically increases the junior partner's bargaining position in policy negotiations. This is especially true when both the CDU and the Tories are in coalition with what might be called their "natural" ideological partner parties from among the available alternatives.

So it is theoretically possible – slightly more so in the FDP's case than the Lib Dems' – that the junior party may respond to current unpopularity by turning in on itself and even breaking into pro- and anti-coalition factions. But it is rather more probable that the larger party will offer further policy concessions. It will do this in the hope of bolstering its partner's popular support without at the same time eating into that of its larger partner or provoking an unmanageable backlash in its own ranks. This is precisely the context of the current UK arguments on control orders and bankers' bonuses.

Talk of staring into the abyss also needs to be handled with care. Not every decline is necessarily terminal. Take the case of the FDP. In every German election since 1949 the FDP has always managed to reach the 5% public support threshold that gives it seats in the Bundestag, thus making it a viable coalition partner. That does not mean it is guaranteed to do so next time, especially in what is nowadays a five-party Bundestag (in another perspective this raises the fascinating possibility of a CDU approach to the Greens). The FDP undoubtedly has work to do to reach the threshold, perhaps by changing its leader. But a liberal, middle-class, low-tax party like the FDP has a plausible continuing place in a nation like Germany, especially in a growing economy.

The equivalent case for Lib Dem durability here is even more robust. While it is true that 7% is lower than any Lib Dem poll rating since 1990, it is also true that the Lib Dem general election share has not fallen below 17% in those years. The Lib Dems are a larger and more entrenched party than their opponents – especially the endlessly patronising Labour party – imagine. Yes they have a dilemma about governing with the left or the right. But look around you – and at the alternatives. There remain plenty of solid reasons for a liberal, socially progressive, anti-strong state, predominantly middle-class party to continue to thrive in British politics.

It's not just the left but also the right that hopes the UK coalition's travails will restore the two-party system and all that goes with it. This week's Spectator magazine is gagging for it. In the short term, yes, there may be some turn in that direction. That's the beauty of unpredictability.

But in the long run the forces pushing Britain towards a more multi-party political line-up like Germany's, and towards some sort of fairer parliamentary electoral system, show few signs of reversing this side of war or economic collapse. Modern politics, in both Britain and Germany, is increasingly marked by greater fairness, greater pluralism and greater volatility. That means there will be more coalitions, not less.

By all means rage against these realities if you choose. By all means dream of turning the clock back to a simpler world. By all means draw attention to what is lost in our politics by such trends. Yet in one form or another, whether you or I like it or not, the smaller parties are here to stay, whatever the result of this or that byelection, or whatever they decide in Baden-Württemberg this spring.